Cockpit display systems often reference multiple different databases in the course of rendering images that include airport features. Non-limiting examples of the referenced databases include a navigation database (NavDB), a runway awareness and advisory system (RAAS), and an Aerodrome Mapping Database (AMDB). With respect to rendering an image of a target runway, runway information referred to as a “runway record” for the target runway is retrieved from available databases. A runway record includes runway-specific information, and one item of that information is a location of the runway threshold, referred to as the runway threshold location. Ideally, regardless of the number of available databases referenced and regardless of the number of received runway records, the runway threshold locations are the same. In practice, for a given runway, the runway threshold locations provided by different runway records may vary. For some airports, there are significant differences between the runway threshold locations within the runway records sourced from the different databases.
A technical problem is presented because the cockpit display system may not be able to determine, for a given runway, that deviations are present, nor which is the most accurate runway record when more than one runway record is available. When an inaccurate runway record is used in a Synthetic Vision System (SVS), the pilot can see a difference between the rendered SVS runway image (i.e., the displayed runway on the cockpit display system) and the actual runway, (i.e., the target runway viewed out of the window). The difference between the SVS runway and actual runway may be distracting to a pilot. Seeing this difference may also have an undesirable consequence of causing the pilot to lose confidence in the SVS generally.
Accordingly, improved cockpit display systems and methods capable of evaluating runway records for accuracy are desirable. The desirable system for selecting accurate runway records determines, from among the multiple different databases, which is providing the most accurate runway record for use in the cockpit display system. The following disclosure provides these technological enhancements, in addition to addressing related issues.